// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This file provides utility functions for "file tasks".
//
// WHAT ARE FILE TASKS?
//
// File tasks are actions that can be performed over the currently selected
// files from the Files app. A task can be one of:
//
// 1) A Chrome Extension or App, registered via "file_handlers" or
//    "file_browser_handlers" in manifest.json (ex. Text.app). This information
//    comes from FileBrowserHandler::GetHandlers()
//
// See also: https://developer.chrome.com/extensions/manifest.html#file_handlers
// https://developer.chrome.com/extensions/fileBrowserHandler.html
//
// 2) Built-in handlers provided by the Files app. The Files app provides lots
//    of file_browser_handlers, such as "play", "mount-archive". These built-in
//    handlers are often handled specially inside the Files app. This
//    information also comes from FileBrowserHandler::GetHandlers().
//
// See also: ui/file_manager/file_manager/manifest.json
//
// For example, if the user selects a JPEG file, the Files app will receive file
// tasks represented as a JSON object via
// chrome.fileManagerPrivate.getFileTasks() API, which look like:
//
// [
//   {
//     "iconUrl":
//       "chrome://extension-icon/hhaomjibdihmijegdhdafkllkbggdgoj/16/1",
//     "isDefault": true,
//     "descriptor": {
//       appId: "hhaomjibdihmijegdhdafkllkbggdgoj",
//       taskType: "file",
//       actionId: "gallery"
//     }
//     "title": "__MSG_OPEN_ACTION__"
//   }
// ]
//
// The file task is a built-in handler from the Files app.
//
// WHAT ARE TASK IDS?
//
// "TaskId" is a string of the format "appId|taskType|actionId". We used to
// store these three fields together in a string so we could easily store this
// data in user preferences. We are removing taskId wherever possible in favour
// of the TaskDescriptor struct, which contains the same information but in a
// more typical struct format. TaskId will remain in some parts of the code
// where we need to serialize TaskDescriptors, like for UMA.
//
// What are the three types of information encoded here?
//
// The "TaskId" format encoding is as follows:
//
//     <app-id>|<task-type>|<action-id>
//
// <app-id> is a Chrome Extension/App ID.
//
// <task-type> is either of
// - "file" - File browser handler - app/extension declaring
//            "file_browser_handlers" in manifest.
// - "app" - File handler - app declaring "file_handlers" in manifest.json.
// - "arc" - ARC App
// - "crostini" - Crostini App
//
// <action-id> is an ID string used for identifying actions provided from a
// single Chrome Extension/App. In other words, a single Chrome/Extension can
// provide multiple file handlers hence each of them needs to have a unique
// action ID. For Crostini apps, <action-id> is always "open-with".
//
// HOW ARE TASKS EXECUTED?
//
// chrome.fileManagerPrivate.executeTask() is used to open a file with a handler
// (Chrome Extension/App), and to open files directly in the browser without any
// handler, e.g. PDF.
//
// Files app also has "internal tasks" which we can split into two categories:
//  1. Tasks that open in the browser. The JS-side calls executeTask(), and we
//     spawn a new browser tab here on the C++ side. e.g. "view-in-browser",
//     "view-pdf" and "open-hosted-*".
//  2. Tasks that are handled internally by Files app JS. e.g. "mount-archive",
//     "install-linux-package" and "import-crostini-image".
//
//  "Virtual Tasks" don't belong to any one app, and don't have a JS
//  implementation. Executing a virtual task simply means running their C++
//  |Execute()| method. See VirtualTask for more.
//
// See also: ui/file_manager/file_manager/foreground/js/file_tasks.js
//

#ifndef CHROME_BROWSER_ASH_FILE_MANAGER_FILE_TASKS_H_
#define CHROME_BROWSER_ASH_FILE_MANAGER_FILE_TASKS_H_

#include <memory>
#include <set>
#include <string>
#include <string_view>
#include <vector>

#include "base/files/file_path.h"
#include "base/functional/callback_forward.h"
#include "chrome/common/extensions/api/file_manager_private.h"
#include "url/gurl.h"

class PrefService;
class Profile;

namespace extensions {
struct EntryInfo;
}

namespace storage {
class FileSystemURL;
}

using storage::FileSystemURL;

namespace user_prefs {
class PrefRegistrySyncable;
}

namespace file_manager::file_tasks {

inline constexpr char kActionIdView[] = "view";
inline constexpr char kActionIdSend[] = "send";
inline constexpr char kActionIdSendMultiple[] = "send_multiple";

// Task types as explained in the comment above. Search for <task-type>.
enum TaskType {
  TASK_TYPE_UNKNOWN = 0,  // Used only for handling errors.
  TASK_TYPE_FILE_BROWSER_HANDLER,
  TASK_TYPE_FILE_HANDLER,
  DEPRECATED_TASK_TYPE_DRIVE_APP,
  TASK_TYPE_ARC_APP,
  TASK_TYPE_CROSTINI_APP,
  TASK_TYPE_WEB_APP,
  TASK_TYPE_PLUGIN_VM_APP,
  TASK_TYPE_BRUSCHETTA_APP,
  // The enum values must be kept in sync with FileManagerTaskType in
  // tools/metrics/histograms/enums.xml. Since enums for histograms are
  // append-only (for keeping the number consistent across versions), new values
  // for this enum also has to be always appended at the end (i.e., here).
  NUM_TASK_TYPE,
};

TaskType StringToTaskType(const std::string& str);
std::string TaskTypeToString(TaskType task_type);

// The SWA actionId is prefixed with chrome://file-manager/?ACTION_ID, just the
// sub-string compatible with the extension/legacy e.g.: "view-pdf".
std::string ParseFilesAppActionId(const std::string& action_id);

// Turns the provided |action_id| into chrome://file-manager/?ACTION_ID.
std::string ToSwaActionId(std::string_view action_id);

// Describes a task.
// See the comment above for <app-id>, <task-type>, and <action-id>.
struct TaskDescriptor {
  TaskDescriptor(const std::string& in_app_id,
                 TaskType in_task_type,
                 const std::string& in_action_id)
      : app_id(in_app_id), task_type(in_task_type), action_id(in_action_id) {
    // For web apps, the action_id must be a full valid URL if it exists.
    DCHECK(task_type != TASK_TYPE_WEB_APP || action_id.empty() ||
           GURL(action_id).is_valid());
  }
  TaskDescriptor() = default;

  bool operator<(const TaskDescriptor& other) const;
  bool operator==(const TaskDescriptor& other) const;

  std::string app_id;
  TaskType task_type;
  std::string action_id;
};

// Describes a task with extra information such as icon URL.
struct FullTaskDescriptor {
  FullTaskDescriptor(const TaskDescriptor& task_descriptor,
                     const std::string& task_title,
                     const GURL& icon_url,
                     bool is_default,
                     bool is_generic_file_handler,
                     bool is_file_extension_match,
                     bool is_dlp_blocked = false);

  FullTaskDescriptor(const FullTaskDescriptor& other);
  FullTaskDescriptor& operator=(const FullTaskDescriptor& other);

  // Unique ID for the task.
  TaskDescriptor task_descriptor;
  // The user-visible title/name of the app/extension/thing to be launched.
  std::string task_title;
  // The icon URL for the task (ex. app icon)
  GURL icon_url;
  // The default task is stored in user preferences and will be used when the
  // user doesn't explicitly pick another e.g. double click.
  bool is_default;
  // True if this task is from generic file handler. Generic file handler is a
  // file handler which handles any type of files (e.g. extensions: ["*"],
  // types: ["*/*"]). Partial wild card (e.g. types: ["image/*"]) is not
  // generic file handler.
  bool is_generic_file_handler;
  // True if this task is from a file extension only. e.g. an extension/app
  // that declares no MIME types in its manifest, but matches with the
  // file_handlers "extensions" instead.
  bool is_file_extension_match;
  // True if this task is blocked by Data Leak Prevention (DLP).
  bool is_dlp_blocked;
};

// Describes how admin policy affects the default task in a ResultingTasks.
enum class PolicyDefaultHandlerStatus {
  // Indicates that the default task was selected according to the policy
  // settings.
  kDefaultHandlerAssignedByPolicy,

  // Indicates that no default task was set due to some assignment conflicts.
  // Possible reasons are:
  //  * The user is trying to open multiple files which have different policy
  //  default handlers;
  //  * The admin-specified handler was not found in the list of tasks.
  kIncorrectAssignment
};

// Represents a set of tasks capable of handling file entries.
struct ResultingTasks {
  ResultingTasks();
  ~ResultingTasks();

  std::vector<FullTaskDescriptor> tasks;
  std::optional<PolicyDefaultHandlerStatus> policy_default_handler_status;
};

// Registers profile prefs related to file_manager.
void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable*);

// Update the default file handler for the given sets of suffixes and MIME
// types. If |replace_existing| is false, does not rewrite existing prefs.
void UpdateDefaultTask(Profile* profile,
                       const TaskDescriptor& task_descriptor,
                       const std::set<std::string>& suffixes,
                       const std::set<std::string>& mime_types,
                       bool replace_existing = true);

// Remove the specified file handler for the given sets of suffixes and MIME
// types.
void RemoveDefaultTask(Profile* profile,
                       const TaskDescriptor& task_descriptor,
                       const std::set<std::string>& suffixes,
                       const std::set<std::string>& mime_types);

// Returns the default task for the given |mime_type|/|suffix| combination in
// |task_out|. If it finds a MIME type match, then it prefers that over a suffix
// match. If a default can't be found, then it returns std::nullopt.
std::optional<TaskDescriptor> GetDefaultTaskFromPrefs(
    const PrefService& pref_service,
    const std::string& mime_type,
    const std::string& suffix);

// Generates task id for the task specified by |app_id|, |task_type| and
// |action_id|.
//
// |app_id| is the Chrome Extension/App ID.
// |action_id| is a free-form string ID for the action.
std::string MakeTaskID(const std::string& app_id,
                       TaskType task_type,
                       const std::string& action_id);

// Converts |task_descriptor| to a task ID.
std::string TaskDescriptorToId(const TaskDescriptor& task_descriptor);

// Parses the task ID, extracts app ID, task type, action ID and returns the
// created TaskDescriptor. On failure, returns std::nullopt.
//
// See also the comment at the beginning of the file for details for how
// "task_id" looks like.
std::optional<TaskDescriptor> ParseTaskID(const std::string& task_id);

// The callback is used for ExecuteFileTask().
typedef base::OnceCallback<void(
    extensions::api::file_manager_private::TaskResult result,
    std::string error_message)>
    FileTaskFinishedCallback;

// Executes file handler task for each element of |file_urls|.
// Returns |false| if the execution cannot be initiated. Otherwise returns
// |true| and then eventually calls |done| when all the files have been handled.
// |done| can be a null callback.
//
// Parameters:
// profile      - The profile used for making this function call.
// task         - See the comment at TaskDescriptor struct.
// file_urls    - URLs of the target files.
// done         - The callback which will be called on completion.
//                The callback won't be called if the function returns
//                false.
bool ExecuteFileTask(Profile* profile,
                     const TaskDescriptor& task,
                     const std::vector<storage::FileSystemURL>& file_urls,
                     FileTaskFinishedCallback done);

// See ash::FilesInternalsDebugJSONProvider::FunctionPointerType in
// chrome/browser/ash/system_web_apps/apps/files_internals_debug_json_provider.h
void GetDebugJSONForKeyForExecuteFileTask(
    std::string_view key,
    base::OnceCallback<void(std::pair<std::string_view, base::Value>)>
        callback);

// Callback function type for FindAllTypesOfTasks.
typedef base::OnceCallback<void(
    std::unique_ptr<ResultingTasks> resulting_tasks)>
    FindTasksCallback;

// Finds all types (file handlers, file browser handlers) of
// tasks.
//
// If |entries| contains a Google document, only the internal tasks of the
// Files app (i.e., tasks having the app ID of the Files app) are listed.
// This is to avoid listing normal file handler and file browser handler tasks,
// which can handle only normal files. If passed, |dlp_source_urls| should have
// the same length as |entries| and each element should represent the URL from
// which the corresponding entry was downloaded from, and are used to check DLP
// restrictions on the |entries|.
void FindAllTypesOfTasks(Profile* profile,
                         const std::vector<extensions::EntryInfo>& entries,
                         const std::vector<GURL>& file_urls,
                         const std::vector<std::string>& dlp_source_urls,
                         FindTasksCallback callback);

// Chooses the default task in |resulting_tasks| and sets it as default, if the
// default task is found (i.e. the default task may not exist in
// |resulting_tasks|). No tasks should be set as default before calling this
// function.
void ChooseAndSetDefaultTask(Profile* profile,
                             const std::vector<extensions::EntryInfo>& entries,
                             ResultingTasks* resulting_tasks);

// Returns whether |path| is an HTML file according to its extension.
bool IsHtmlFile(const base::FilePath& path);

// Whether we have an explicit user preference stored for the file handler for
// this extension. |extension| should contain the leading '.'.
bool HasExplicitDefaultFileHandler(Profile* profile,
                                   const std::string& extension);

}  // namespace file_manager::file_tasks

#endif  // CHROME_BROWSER_ASH_FILE_MANAGER_FILE_TASKS_H_